Multicast transmissions are unreliable because they are sent onto a medium subject to collisions, but without a retry or inter-packet Forward Error Correction (FEC) mechanism. Directed Multicast Service (DMS) performs a multicast to unicast conversion (M2U2C) of a multicast stream. When a multicast stream is sent as a unicast stream, it inherits the unicast retry mechanism. However, this scheme is inefficient, and in some cases, such as very large groups and/or video flows with high bandwidth requirements, impossible. Group Cast Retries (GCR), formerly known as More Reliable Groupcast (MRG), improves multicast reliability. GCR supports multiple acknowledgement (ACK) policies, including M2U2C, unsolicited retries, also known as repeat-x, and a Block Ack (BA) mechanism. The BA mechanism may be a Full State BA or a partial state BA. Partial state BA imposes certain restrictions on transmissions, for example there can be only one outstanding flow, identified by a TID (“Traffic Identifier”), at the receiver that is waiting for a BAR.